6. MAINTENANCE & TROUBLESHOOTING
6-7
Range changed but
radar picture does not
change
1) Defective range key
2) SPU board
3) Video freeze-up
1) Try to operate the
RANGE
key. If unsuc-
cessful, replacement of the keypad may
be necessary.
2) Replace SPU board.
3) Turn radar off and on.
Interference rejector
is not working (inter-
ference rejection
level not displayed)
1) SPU Board
1) Replace SPU Board.
Echo stretch is not
working (Neither
ES1, ES2 or ES3 is
displayed)
1) SPU Board
1) SPU Board
Range rings are not
displayed
1) Adjust their brilliance on the
Brill/Color menu.
2) SPU Board
1) Replace associated circuit board if unsuc-
cessful.
2) Replace SPU Board.
Poor discrimination in
range
Sea clutter control not func-
tioning properly
Improper adjustment of
SEA
control.
True motion presen-
tation not working
properly
1) Poor contact of
MODE
key.
2) TM display accurate
1) Try to press the key a little harder.
2) Make sure that speed and compass
inputs are accurate.
Target not tracked
correctly
Poor definition of targets in sea
clutter
Adjust
SEA
and
RAIN
controls.
Advanced-level troubleshooting
Problem
Probable cause or
check points
Remedy